Many types of disposable consumer products such as diapers, training pants, feminine care articles, incontinence articles, and the like, utilize an absorbent pad structure for absorbing and wicking away bodily fluids. The absorbent pads are conventionally formed from an absorbent web, typically a non-woven fibrous web material. With one particular general practice, the absorbent web is formed by employing conventional airlaying techniques wherein fibers and typically a superabsorbent material are mixed and entrained in an air stream and then directed onto a forming surface to form the web. The absorbent web may then be directed for further processing and assembly with other components to produce a final absorbent article. An advantage of this practice is that trim waste can be immediately recycled by returning the waste to the upstream fiberizing equipment and/or airlaying equipment.
With another conventional technique, preformed absorbent web sheets or layers are delivered into a manufacturing line from a preformed supply, such as a supply roll. The absorbent sheet material may be separated into adjacent strips having various configurations of repeat pattern “nested” shaped pads wherein the shape of one pad is substantially nested with the shape of at least one immediately adjacent pad.
The preformed absorbent material roll process presents particular challenges. For example, the geographical separation of the base roll-making machine makes recycling of the trim waste impractical and cost prohibitive. In this regard, the nesting feature mentioned above has been desirable to reduce the amount of waste that is generated from the originally supplied (roll) of absorbent web. However, with conventional nesting techniques and profiles, a considerable amount of trim waste is still generated.
Also, the more easily processed strip-shapes have a repeat pattern that is substantially symmetrical with respect to its longitudinal dimension that coincides with the machine direction of the web. With such longitudinally-symmetric nested patterns, a single cycle of the repeat pattern provides an individual web segment wherein the shape of a first lengthwise half portion of the segment substantially matches the shape of the longitudinally opposed other half portion. However, for certain consumer absorbent articles, it has been found desirable from a product fit, comfort, and performance standpoint to shape the pad so that it is longitudinally asymmetric. For example, the pad may have a wider front or “ear” portion as compared to the back portion. Unfortunately, such configurations in a nested pattern add to the amount of generated waste.
Also, it may be desirable to provide a higher basis weight of absorbent material in the crotch portion as compared to the front and back portions. This has conventionally been done by folding or otherwise adding additional absorbent material (e.g., additional layers) into the crotch area.
The present invention provides a method for producing longitudinally symmetric or asymmetric absorbent pad structures in a roll process with minimal or zero waste of the roll material.